Finding the Fourth Proportional to 1,209.61, 1,815.35 and 885.82

Step by Step Solution

1. Step 1: Write the proportion equation
   1,209.61 : 1,815.35 = 885.82 : x
2. Step 2: Convert to fraction form
   1,209.61/1,815.35 = 885.82/x
3. Step 3: Cross multiply
   1,209.61x = 1,815.35 × 885.82
4. Step 4: Simplify right side
   1,209.61x = 1,608,073.34
5. Step 5: Solve for x
   x = 1,608,073.34/1,209.61
6. Step 6: Final answer
   x = 1,329.41